1. Field of the Invention
The present invention relates to the process of updating a name-server database. More specifically, the present invention relates to a method and apparatus for updating resource records in a name-server database by sending an update-request message to a name server, wherein the update-request message includes a requested lease, which specifies a length of time for which the name server is being requested to store the resource-record updates.
2. Related Art
The Domain Name System (DNS) is a distributed system that provides a global naming service. Like many other services, DNS was designed for essentially a static network, in which the global namespace was expected to change infrequently. Since the frequency of changes was expected to be fairly low, DNS was not designed to handle dynamic updates.
Subsequently, DNS has been extended to support dynamic updates. IETF (Internet Engineering Task Force) RFC (Request For Comments) 2136 specifies an extension to DNS, which allows DNS to handle dynamic updates. In this extension, a network node, such as a laptop, is required to provide explicit updates to the DNS name server.
Unfortunately, this extension can cause the DNS name server to contain stale information. Consider, for instance, a mobile user whose laptop updates the DNS name server via dynamic update. Note that, the updates will continue to remain on the DNS name server, until they are explicitly deleted. For example, if the user unplugs the laptop from the network without explicitly deleting the updates, the updates will continue to remain on the DNS name server indefinitely. This can be a serious problem, because it causes the DNS name-server database to contain stale information, which reduces the accuracy and usefulness of the DNS name-server database.
“DNS Scavenging” is an attempt to address the above problem. In “DNS Scavenging,” a client network-node, such as a laptop, and the DNS name server are configured with a preset refresh interval. Unfortunately, this method works only if both the laptop and the DNS name server are configured with compatible refresh intervals, which can only be guaranteed if they are under the same administration. In many situations, the laptop and the DNS name-server are under different administrations. Hence, “DNS Scavenging” is severely limited in its use.
Hence, what is needed is a method and apparatus for dynamically updating a name-server database without the above-described drawbacks.